From cd464d8e223ca2137e9d985a52eb7d8ba4a15180 Mon Sep 17 00:00:00 2001
From: Matthias Kruk <m@m10k.eu>
Date: Sat, 10 Apr 2021 08:34:26 +0900
Subject: [PATCH] include/ssh: Simplify SSH module API

The ssh_tunnel_close() and ssh_proxy_close() functions do essentially
the same thing, so they should be merged into one. Further, both of
the functions require the user to remember multiple values from the
ssh_*_open() call in order to close the connection. This seems
unnecessarily complicated.
This commit adds the ssh_close() function as a replacement for
ssh_tunnel_close() and ssh_proxy_close(). Further, the ssh_*_open()
functions now return a handle that can be passed to ssh_close() to
close the respective connection.
---
 include/ssh.sh | 133 ++++++++++++++++++++++++++++++-------------------
 1 file changed, 82 insertions(+), 51 deletions(-)

diff --git a/include/ssh.sh b/include/ssh.sh
index fe1d32c..a452a7b 100644
--- a/include/ssh.sh
+++ b/include/ssh.sh
@@ -56,100 +56,131 @@ _ssh_proxy_ctrl_socket_name() {
 	return 0
 }
 
-ssh_tunnel_open() {
-	local tunnel_host
-	local tunnel_user
-	local remote_addr
-	local remote_port
-	local local_addr
-	local local_port
-
-	tunnel_host="$1"
-	tunnel_user="$2"
-	remote_addr="$3"
-        remote_port="$4"
-	local_addr="$5"
-	local_port="$6"
+_ssh_make_handle() {
+	local ctrlsock="$1"
+	local hostspec="$2"
 
-	local ctrl_sock
-	local addrspec
-	local sshtarget
+	local handle
 
-	if ! ctrl_sock=$(_ssh_tunnel_ctrl_socket_name "$remote_addr" \
-						      "$remote_port" \
-						      "$local_port"); then
+	if ! handle=$(base64 <<< "$ctrlsock" 2>/dev/null); then
 		return 1
 	fi
 
-	addrspec="$local_addr:$local_port:$remote_addr:$remote_port"
-	sshtarget="$tunnel_user@$tunnel_host"
+	handle+=":"
 
-	if ! ssh -M -S "$ctrl_sock" -fnNT -o "ExitOnForwardFailure=yes" \
-	     -L "$addrspec" "$sshtarget" > /dev/null; then
+	if ! handle+=$(base64 <<< "$hostspec" 2>/dev/null); then
+		return 1
+	fi
+
+	echo "$handle"
+	return 0
+}
+
+_ssh_handle_get_ctrlsock() {
+	local handle="$1"
+
+	local ctrlsock
+
+	if ! ctrlsock=$(base64 -d <<< "${handle%%:*}" 2>/dev/null); then
+		return 1
+	fi
+
+	echo "$ctrlsock"
+	return 0
+}
+
+_ssh_handle_get_hostspec() {
+	local handle="$1"
+
+	local hostspec
+
+	if ! hostspec=$(base64 -d <<< "${handle##*:}" 2>/dev/null); then
 		return 1
 	fi
 
-	echo "$ctrl_sock"
+	echo "$hostspec"
 	return 0
 }
 
-ssh_tunnel_close() {
-	local tunnel_host
-	local tunnel_user
+ssh_tunnel_open() {
+	local tunnel_host="$1"
+	local tunnel_user="$2"
+	local remote_addr="$3"
+	local remote_port="$4"
+	local local_addr="$5"
+	local local_port="$6"
+
 	local ctrl_sock
+	local addrspec
+	local sshtarget
+	local handle
+
+	addrspec="$local_addr:$local_port:$remote_addr:$remote_port"
+	sshtarget="$tunnel_user@$tunnel_host"
 
-	tunnel_host="$1"
-	tunnel_user="$2"
-	ctrl_sock="$3"
+	if ! ctrl_sock=$(_ssh_tunnel_ctrl_socket_name "$remote_addr" \
+						      "$remote_port" \
+						      "$local_port"); then
+		return 1
+	fi
 
-	if ! ssh -S "$ctrl_sock" -O exit "$tunnel_user@$tunnel_host" &> /dev/null; then
+	if ! handle=$(_ssh_make_handle "$ctrl_sock" "$sshtarget"); then
 		return 1
 	fi
 
+	if ! ssh -M -S "$ctrl_sock" -fnNT -o "ExitOnForwardFailure=yes" \
+	     -L "$addrspec" "$sshtarget" > /dev/null; then
+		return 1
+	fi
+
+	echo "$handle"
 	return 0
 }
 
 ssh_proxy_open() {
-	local proxy_host
-	local proxy_user
-	local local_addr
-	local local_port
+	local proxy_host="$1"
+	local proxy_user="$2"
+	local local_addr="$3"
+	local local_port="$4"
 
 	local ctrl_sock
 	local addrspec
 	local sshtarget
+	local handle
 
-	proxy_host="$1"
-	proxy_user="$2"
-	local_addr="$3"
-	local_port="$4"
+	addrspec="$local_addr:$local_port"
+	sshtarget="$proxy_user@$proxy_host"
 
 	if ! ctrl_sock=$(_ssh_proxy_ctrl_socket_name "$local_addr" "$local_port"); then
 		return 1
 	fi
 
-	addrspec="$local_addr:$local_port"
-	sshtarget="$proxy_user@$proxy_host"
+	if ! handle=$(_ssh_make_handle "$ctrl_sock" "$sshtarget"); then
+		return 1
+	fi
 
 	if ! ssh -M -S "$ctrl_sock" -fnNT -o "ExitOnForwardFailure=yes" \
 	     -D "$addrspec" "$sshtarget" > /dev/null; then
 		return 1
 	fi
 
-	echo "$ctrl_sock"
+	echo "$handle"
 	return 0
 }
 
-ssh_proxy_close() {
-	local proxy_host
-	local proxy_user
-	local ctrl_sock
+ssh_close() {
+	local handle="$1"
 
-	proxy_host="$1"
-	proxy_user="$2"
-	ctrl_sock="$3"
+	local ctrlsock
+	local hostspec
+
+	if ! ctrlsock=$(_ssh_handle_get_ctrlsock "$handle") ||
+	   ! hostspec=$(_ssh_handle_get_hostspec "$handle"); then
+		log_error "Invalid handle"
+		return 1
+	fi
 
-	if ! ssh -S "$ctrl_sock" -O exit "$proxy_user@$proxy_host" &> /dev/null; then
+	if ! ssh -S "$ctrlsock" -O exit "$hostspec" &> /dev/null; then
 		return 1
 	fi
 
-- 
2.47.3